For the resistor color codes, it is necessary to understand the corresponding relationship between the colors and the Arabic number. So I find some material to learn it, the color in different positions has different digital meanings, that is, the colors representing different values( learning from an article https://www.kynix.com/Blog/481.html). But the distance between the color rings will also affect the degree of recognition, which is really very difficult. I have read many similar articles about it, but I‘m getting more and more confused? Is there any one can give me some advice ? more systematic and simple, may be give some examples to explain.

Any efficient info or suggestions would really appreciated, thank you in advance.

The space between color stripes is not important; but the really wide gap separates the value stripe from the tolerance and temperature coefficient stripes.

The first value stripe will always indicate 1 through 9 (never 0), then you always assume a decimal point. The last stripe before the wide gap is the multiplier exponent (10 to the value of color). The stripes between the first and last are for the tenths, hundredths, etc digits.

Many, maybe Most modern resistors (leaded types) are now marked with a numerical code. Don't you think color codes are almost obsolete?

In any case, there are apps if your eyes aren't up to he task. I always had trouble because color shades vary from maker to maker and background colors also make them hard to read consistantly. Today they have technology to print small letters and unless you are pulling from a marked stock box, often need to measure to confirm.

I looked in the play store and I was wrong, While there are many resistor color code calculators, there were few scanners or readers and reviews complained they were often inaccurate, I suspect you need to image with no background colors with good light. I didn't try any.

Looking in Digikey, I see there are still plenty. What surprised me is the note "Tariff Applied" to the pricing column. That's outrageous, first time in my entire career I have seen duties on components. No wonder the market is tanking

I wasn't being short with you. I had just lost the longer answer down the black hole of pressing submit.

The link you gave does use the phase "color codes obsolete", then proves they are not. In more and more electronics in the world SMT (which does not use color code) is used. So less percentage ofcolor coded components "in existance" is true.

But how does an idea get from paper to 1000000 units produced by robot? You do not set up a robot assembly line for a one-off prototype. Then there are short run eqiupments where robot assembly may not make sense. And, even on mass produced items they probably go with color coded axial leads for a 1/4W or more.

Those miniscule unmarked components will be loaded in zillion quantity barcoded cartridges, and machines will pluck-n-stuff at the speed of zeuss.
Hobbyist and small producers will be allowed to buy the end rolls and floor sweepings of unmarked parts in ....Poly Paks, if anyone still remembers them.
The parts will not be cheap, because of the money-grab trariff and the EPA will be out searching for any miscreants, that might dispose of spent etching, wih their drones since they have given up looking for wacky weed. Plus, with the general overall apathy of the aged hobby group, we likely won't be too interested in even using the parts since we can't see them or pick them up, plus most everything can be bought better and cheaper than can be built.

It's really a shame they are limiting electronic refuse in landfills! Someday that may well be the only source of 'cheap' and availabe human sized parts for the dwindling fraction of remaining die-hard techno-hackers.

Orwellian rant done!

Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)

To make things harder, there were a few resistor manufacturers that graded the body color (light grey, beige, light blue, lightr brown...) as a temperature or something else cohefficient. Cannot remember now what it was....

But how does an idea get from paper to 1000000 units produced by robot? You do not set up a robot assembly line for a one-off prototype. Then there are short run eqiupments where robot assembly may not make sense. And, even on mass produced items they probably go with color coded axial leads for a 1/4W or more.

Primarily manufacturing methods are driven by the capabilities of the contract manufacturer the OEM is using , the experience of the design engineer, and lessons learned by the company *the OEM" he works for. For most commercial products, thru hole technology (THT) is not a good option, it usually cannot be machine assembled and may be plagued by old date codes and other manufacturing shortcomings. THT is great for prototypes and sometimes the only choice for some types of components like connectors but SMT is preferred by manufacturers because it can be assembled by a pick and place machine, fed by tape and reel, tube or tray component packaging. These robots are still operated and configured by humans for each job.

Actual product floorplans (PCBs and other component locations) are driven mainly by the form factor of the product but moderated by assembly concerns from component to subassembly to final assembly and packaging. An experienced company will plan for test equipment interfaces, Automated video inspection (machine vision) and assembly jigs when developing a product all of which is balanced against cost and intended manufacturing volumes. The rate of manufacture is also key. A good plan is scalable where you can parallel your jigs and assembly plans out as many times as you need to meet demand without spending so much on tooling that if the product fails, you don't go broke. This is where contract assemblers are essential, you get a flexible assembly work force you don't have to lay off when you are done. Other consulting and support companies also thrive in the design to manufacturing ecosystem, there are many choices on and off shore to turn a paper design (really electronic) to a physical thing.

Color coding probably does OK with machine vision inspection systems as long as you don't change the supplier too often (and the appearance) but that's true of any inspected component. Its just unlikely to be used for high volume because they are thru hole